Motor



March zz, 1927. i 1,621,937

R. L. LEE

MOTOR Filed Nov. 24, 1923 Patented Mar. 22, '1927.

UNITED STATES 'FFICE BALPI-I L. LEE, OF IDAYTON, EIO, ASSGNOR TG DELCC-LE' .EET COMPANY, 033' DAYTON, OHIO, A COBORATO OF BELA'WABE.

MOTOR.

Application filed November 24, 1923.

The invention relates to series electric motors and particularly to apparatns for preventing racing` or overspeeding,` under light loads or under no load.

The racing of m'otors has been prerented by providing the motor armature with circuits including one or more closed loops surrounding certain of th-e armature core teeth. Currents induced in these loops tend to hold back the armature of the motor and thereby tend to prevent orerspeeding of the armature.

One of the objects of the inrention is to simplify the mann-er of constructing the closed loops, and to accomplish this aim, One form of the inveution includes an openslotted laminated armature core having strips of conducting material extending along the slots and electi'ically connected with certain end laminations of the armature core.

Further objects and advantages of the presentinvention will be apparent from the following description, reference being;` had to the accompanying drawings, wherein a preferred einbodiment of one form of the present invention is clearly shown.

In the drawings:

Fig. 1 is a View in eleration of an armature including` the present invention.

Fig. 2 is a. sectional View taken on the line 2-2 of Fig. 1, the armature windings being shown in but one of the armature slots.

Referring to the dra-wings, an armature 20 of the series wound type is provided with a laminated core 21 mounted on a shaft 22 and having open slots 23 in which armatnre windings 24 are adapted to be laid. The windings 24: are insulated from the core 21 by a split sleeVe 25, preferably of fish paper. A strip of fish paper 26 is slipped along` the slot 23 over the top of windings 2% to cover the slit in sleeve 25. A stick 27, of insulating material, such as fiber, of a width greater than the width of the month opening 28 of slot 28, is driven into the slot 23 from the end thereof. The edges of the stick 27 engage the curved surfaces 29 and 30 of the slot 23 and wedge the windings 24, paper sleeve 25 and paper strip 26 securely within the slot 28. Stick 2.7 is somewhat longer than the slot 23 so that when inserted in the slot 23, the ends thereof ex- Seral No. 61152831.

tend beyond the ends of slot 23 for a purpose to be described.

The last few laminations on each end of core 21 are plated, before the core is assembled on shaft 22, with one of the metals of which a solder oompound may be composed, such as t-in. Then strips or bars 31 of conductin` material preferably of rela- -tively high resistance, which have also been plated with a similar metal, are inserted from the ends of slots 23 along` the top of sticks 27. These strips 31 are substantially as long as slots 23, and are greater in width then the month opening,` 28 of slot 28. `houlders 82 and 38 tend to maintain strips 31 within the slots 23. Strips 31 are electrically connected at their ends with the plated end laminations by (Llropping` solder on the ends of said strips and permitting;` the solder to flow to the plated laminations. The plating` of strips 31 and the end laminations of the core permit soldering without the use of acid, which would be detrimental to windings 2a 'should it drop upon them. The portions of sticks 27 extending beyond the ends of slots 28 preyent solder dropping,` down upon the armature windings and thus causing short circuits.

W] hen the motor is under a light load or no load, the field thereof will be weak and the armature will tend to speed up. Currents induced in the closed loops formed by strips 31 around the core teeth tend to oppose the current flowing in windings 211 and thus cut down the speed of the arinature. By using a relativeiy large number of strips 81 in the armatnre core, the heat gene *ated in these strips is more evenly distributed about the armature and hot spots are avoided.

While the form of enibodiment of the in- Vention as lerein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

lllhat is claimed is as follows:

1. An armature comprising, in combination, a plurality of lamin placed side by side to provide a single core, said core being` provided with slots extending axially ther-ewith, armature .indings within said slots, and conductor bars within said slots the opposite ends of said bars being secured to a plurality of laminze at the opposite ends of said core for preventing racing of the armature.

2. An `arlfna'ture comprisng lin combinaton7 a core provided With slots,v armature Windi'ngs Within said slots, sieev-es for 'insulating the Windings from 'the core, means for retaining the sleeves and windings in the slots, and conducting bars supported Iby said means Within the slots and electrically connected adjacent their ends With-said core for preventing racing of the armature.

3. An 'armature coniprsing, in combination, a plnrality of lanfinee placed side by side to provide a single core, said core be- -ing ;provided with slots extending axially therewith, armature Windings within said slots, and conductor bars VWithin said slots, `land located 'nearer 'to the periphely 'of the core than the armature Windngs, and connected With the core adjacent op aositeends Ithereof for prev-enting racing o the armature. i

In testimony Whereof I hereto afiix rny signature.

RALPH L. LEE. 

